1. Field of the Invention
The invention relates to novel substituted pyridinyl phosphonamidates, phosphonamidothioates, phosphorodiamidates and phosphorodiamidothioates and to their use in the control of soil nematodes.
2. Description of the Prior Art
Demosay et al. in U.S. Pat. No. 3,669,975, teach pesticidal activity, including nematicidal activity, for certain 6-methyl-3-pyridyl phosphates and thiophosphates having as an essential feature of the molecule RO substituent on the phosphorus atom. There is no exemplification of nematicidal activity in the patent disclosure and compounds such as O,O-diethyl O-(6-methyl-3-pyridinyl) thiophosphate have been found to have little or no nematicidal activity at reasonable field application rates. Moveover, while O-(6-methyl-3-pyridinyl) N-methyl ethylphosphoramidothioate has been found to exhibit some nematicidal activity, O-(6-methyl-3-pyridinyl) N-methyl ethylphosphonamidothioate is not similarly active. The nematicidal activity of these compounds is clearly not as predictable as might be deduced on reading Demosay et al.
Rigterink, in U.S. Pat. No. 3,743,648, discloses and claims pesticidal pyridinyl phosphates and phosphorothioates having, as an essential feature, a trifluoromethyl group on the pyridinyl ring. While the broad teachings are not so limited, each of the examples of Rigterink show a 2-pyridinyl or 4-pyridinyl compound. Furthermore, in those compounds of Rigterink in which notable nematicidal activity was found, the CF.sub.3 group is at the 4-position and the ester-oxygen linkage is at the 2-position of the pyridinyl ring.